In connection with an increasingly more advanced use of linear hydraulic, pneumatic and electric actuators, there has arisen a need for new sensor solutions therefor. In the oil industry there exists a need associated with measurement of the stroke/position of hydraulic cylinders, which cylinders may have stroke lengths in the area of about ten meters and longer. In such hydraulic cylinders, solutions based on gun-drilled holes in piston rods are extremely cost-intensive, and at the same time preclude the replacement of sensors without the whole cylinder being dismantled for renovation. The existing solutions will thus have a number of challenges associated with robustness, accuracy, price and retrofittability.
In connection with regular integrity measurements and monitoring of rotary and translatory elements, there are a number of challenges. One of these challenges is to establish the necessary contact with moving elements in a reliable and long-time stable manner. An example of an application may be continuous monitoring of train axles for, for example, fatigue. Another area may be continuous measurements of shafts in vessels and other similar machine elements that may be subject to reciprocating load with subsequent fatigue cracks and/or other phenomena it is desired to monitor and/or measure in connection with the integrity of machine elements.
An object according to the present invention is therefore to provide a system for position measurement and integrity measurement, wherein one or more disadvantages of the prior art are eliminated or at least minimised.
Another object of the present invention will be to provide a system for position measurement and integrity measurement, where retrofitting on existing cylinders, axles or similar devices is made possible in a simple manner and with a good, producible, robust and long-time stable result.
Yet another object according to the present invention will be to provide a system for position measurement and integrity measurement, where the integrability in the structure of existing products and as a part of existing components is made possible in a simple manner and with a good, producible, robust and long-time stable result.
These objects are achieved by means of a system for position measurement and integrity measurement as disclosed in the following independent claims, with additional features of the invention set forth in the dependent claims and description below.